package com.pet.system.common;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class SpringContextHolder implements ApplicationContextAware {
    ApplicationContext applicationContext;
    private static final Map<String, ApplicationContext> map = new ConcurrentHashMap<>();

    /**
     * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
     */
    public void setApplicationContext(ApplicationContext applicationContext) {
        map.put("applicationContext", applicationContext);
    }

    /**
     * 取得存储在静态变量中的ApplicationContext.
     */
    public static ApplicationContext getApplicationContext() {
        checkApplicationContext();
        return map.get("applicationContext");
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) {
        checkApplicationContext();
        return (T) map.get("applicationContext").getBean(name);
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(Class<T> clazz) {
        checkApplicationContext();
        return (T) map.get("applicationContext").getBeansOfType(clazz);
    }

    /**
     * 清除applicationContext静态变量.
     *
     */
    public static void cleanApplicationContext() {
        map.remove("applicationContext");
    }

    private static void checkApplicationContext() {
        if (map.get("applicationContext") == null) {
            throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");
        }
    }
}
